Fluid diaphragm modulator

ABSTRACT

A pair of spaced and series connected nozzles terminate in a first coupling chamber with a flat spring-loaded diaphragm forming an outer wall. A second coupling chamber closes the spaces between the nozzles. The diaphragm is a common wall with an input chamber. A main fluid supply is connected to either the first coupling chamber or to the first nozzle and an output or a reference pressure means is correspondingly connected to the second coupling chamber. A supply to the nozzle establishes aspiration between the two nozzles with a resulting negative pressure level. A control input signal to the input chamber moves the spring-loaded diaphragm toward the second nozzle with an increased pressure in the second chamber. Alternatively, the output is connected with the supply to the first chamber and the nozzles and second chamber are connected to references to establish unit gain and provide a repeater.

United States Patent 1 1 1 3,734,117 Atkinson [4 May 22, 1973 [54] FLUIDDIAPHRAGM MODULATOR Primary ExaminerAlan Cohan t L D. Atk N B l ,W [75]or mus mson cw er m ls Attorney-Andrus, Sceales, Starke & Sawall and Ar-[73] Assignee: Johnson Service Company, Milwauld J D A li kee, Wis. 22Filed: Nov. 18,1970 [57] ABSTRACT A pair of spaced and series connectednozzles ter- [21] Appl' 90707 minate in a first coupling chamber with aflat springloaded diaphragm forming an outer wall. A second [52] US. Cl..l37/82 coupling chamber closes the spaces between the noz- [51] Int.Cl ..G05d 16/00 zles. The diaphragm is a common wall with an input [58]Field of Search ..137/82, 83, 85, 81.5; chamber' A main fluid supply isconnected to either the first coupling chamber or to the first nozzleand an output or a reference pressure means is cor- [56] ReferencesCited respondingly connected to the second coupling chamber. A supply tothe nozzle establishes aspiration UNITED STATES PATENTS between the twonozzles with a resulting negative 3,576,131 4/1971 Calderazzo ..73/37.5pr re level. A control input signal to the input 3,250,116 5/1966 Hatch...73/37.5 chamber moves the spring-loaded diaphragm toward 3,150,6749/1964 C gh /8 the second nozzle with an increased pressure in the3,461,896 Holloway second chamber Alternatively nhg output is on-3,169,402 2/1965 Baker ....l37/85 X nected with the Supply to the firstChamber and the 3,566,899 3/1971 Bowditch ..l37/82 nozzles and secondchamber are connected to FOREIGN PATENTS OR APPLICATIONS refetrences toestablish unit gain and provide a reea er. 1,029,826 5/1966 GreatBritain ..73/37.5 p

648,844 11/1962 ltaly ..l37/82 8 Claims, 6 Drawing Figures ZZ [4/8 iPATENTE M22 1875 inpyt FIGJ 4 L V///////F/ IOV wOutput FIG? INVEN TonLOUIS D. ATKINSON Attorneys FLUID DIAPHRAGM MODULATOR BACKGROUND OF THEINVENTION This invention relates to a fluid diaphragm modulator oramplifier for producing a fluid control signal in response to an inputfluid signal.

Diaphragm amplifiers are employed in the fluid control art to provide anisolated high power output fluid signal which is controlled by arelatively low power input signal. Generally, diaphragm amplifiersinclude a movable diaphragm unit defining an input chamber to one sideof the diaphragm and a control or modulating chamber to the oppositeside. The input pressure signal is applied to the input chamber toposition the diaphragm with respect to one or more power stream orifices.

The relative positioning of the diaphragm with respect to the orificesdetermines the output signal pressure and flow, thereby permittingcontrol of a high pressure stream by a relatively low pressure signal.Diaphragm amplifiers may advantageously be designed with a high inputimpedance but are generally restricted to modulating between a firstpressure level above a reference and a higher level.

SUMMARY OF THE PRESENT INVENTION The present invention is particularlydirected to a diaphragm modulator permitting high gain with high inputimpedance, and establishing an output signal which may vary above andbelow a reference pressure and permit operation of the modulator as anamplifier or as a repeater with only a change in external tubingconnections required. Generally, in accordance with the presentinvention, a pair of spaced and series connected nozzles terminate in adiaphragm-control unit and particularly a coupling chamber positioned atthe discharge end of the stacked nozzles. The spacing between thenozzles is closed by a second coupling chamber providing a secondconnection to the fluid system. A control diaphragm forms at least apart of the wall of the coupling chamber, whichwall is opposed to theorifice of the second nozzle within the coupling chamber and therebycontrols the effective opening of the orifice. The diaphragm is also acommon wall with an input chamber of the diaphragm control unit. Thediaphragm is resiliently loaded to a control position in spaced relationto the nozzle orifice.

A main fluid supply is connected to either the firs coupling chamber orthe input nozzle and a control signal is connected to the signal inputchamber. An output or a reference pressure means is correspondinglyconnected to the second coupling chamber.

With the supply connected to the first nozzle as an input, a fluidstream is established from the supply through the two nozzles into thefirst coupling chamber, which is also connected to a reference pressure.The stream establishes aspiration between the two nozzles with aresulting negative pressure level in the second coupling chamber whichis connected to an output means. This permits reducing the output rangebelow a zero pressure reference level. A control input signal to theinput chamber moves the resiliently loaded diaphragm toward the orificeof the second nozzle, with the resulting increase in back pressure andactual diversion of the stream into the intermediate or second couplingchamber. The output pressure will thus rise from the aspirated level,with the pressure being proportional to input signal. When the diaphragmis forced by the input signal to completely cover the opposed orificeand close it off, a maximum output pressure is established in the secondcoupling chamber.

By connecting of a stream supply means and an output means to the firstcoupling chamber, and connecting the second coupling chamber and firstor input nozzle to a reference or an exhaust, the apparatus functions asa fluid repeater. The pressure in the first coupling chamber will bedirectly related to the exhausting condition which is now controlled bythe effective opening of the second nozzle orifice. Thus, with the inputsignal removed and the diaphragm wall means in the neutral position, thefirst coupling chamber is freely referenced to the respective nozzles.

As an input signal is established, the diaphragm wall moves toward thecollector orifice, thereby restricting the passageway therefrom. Thiswill increase the pressure in the first coupling chamber and thereforethe output pressure until such time as the orifice is completely closed,at which time, the output pressure will be equal to the supply pressure.

The present invention thus provides an improved fluid amplifier whichpermits operation between negative and positive pressure levels, as wellas maintaining high gain and high input impedance characteristics of thediaphragm amplifier.

DESCRIPTION OF THE DRAWING The drawing, furnished herewith, illustratesthe preferred construction of the present invention in which the aboveadvantages and features are clearly disclosed as well as others whichwill readily be understood from the following description.

In the drawing:

FIG. 1 is a vertical cross-sectional view of a diaphragm amplifierconstructed in accordance with the present invention;

FIG. 2 is a plan view of the diaphragm amplifier shown in FIG. 1 withthe several fluid supply and output connections diagrammaticallyillustrated;

FIG. 3 is a sectional view taken generally on line 3-3 of FIG. 2;

FIG. 4 is a sectional view taken generally on line 4-4 of FIG. 2; a

FIG. 5 is a sectional view taken generally on line 5-5 of FIG. 1 toillustrate the preferred spring construction; and

FIG. 6 is a vertical section through a diaphragm amplifier constructedin accordance with the present invention and interconnected to fluidmeans to establish a fluid repeater.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing and,particularly, to FIGS. 1 and 2, a diaphragm amplifier unit 1,constructed in accordance with the teaching of the present invention, isillustrated having a first port 2 connected to a suitable pressurizedfluid supply 3. The diaphragm unit 1 is particularly adapted forapplication in pneumatic systems wherein an air supply 3 is employed andthe application is hereinafter described in connection with such asupply. Within the broadest aspects of the present invention, however,the device is equally applicable to other fluid supplies.

In the embodiment of FIGS. 1 and 2, a pair of ports 4 and 5 are shownconnected to a suitable pneumatic responsive output 6. The relativeoutput pressure and flow is controlled by a pair of exhaust ports 7 and8 connected to selectively vent the supply port 2 to a suitablereference 9, such as atmosphere. The proportionate exhausting orbleeding to reference is controlled by a diaphragm 10, the position ofwhich is responsive to an input or control signal applied at a controlport 11.

A suitable control signal source 12 is connected to the port 11 tovariously position the diaphragm in accordance with the input signalpressure level. As more fully described hereinafter, the output pressureis directly related to the input signal pressure.

More particularly, the illustrated amplifier includes a base 13 havingthe upper wall thereof recessed to define with an intermediate ledge 14.The periphery of diaphragm 10 rests on a ledge 14 with a flat spring 15disposed in overlying relationship upon the diaphragm. The ledge 14 isprovided with a raised, clamping edge 16 to provide an essential lineengagement with the diaphragm 10. An intermediate wall 17 includes adownwardly projecting angular wall 18, which telescopes into therecessed portion of the base 13 in alignment with the ledge 14. Theintermediate wall 17 is secured to the base 13 in any suitable manner asby a pressed fit, positive interconnecting means or the like to clampthe inner face of the angular wall 18 against the peripherial portion ofthe spring 15, and thereby clamp the diaphragm l0 tightly against theedge 16 to establish a fluid-tight joint. This establishes an inputchamber 19 between the diaphragm 10 and the base of the recess, which isinterconnected to the input port 11.

As most clearly shown in FIG. 4, the underside of the base 13 isprovided with a stepped recess to define a connecting port 20 betweenthe chamber 19 and a capped chamber 21. The port 11 projects upwardlyand outwardly from chamber 21 to provide an input signal to the sealedand dead-ended chamber 19, thereby producing the desirable high inputimpedance. The input signal establishes a fluid pressure tending to urgethe diaphragm 10 and the spring member 15 upwardly of the chamber 19 andinto the recess defined by intermediate wall 17.

The wall 17, as previously noted, includes the angular wall 18, whichdefines the first coupling chamber 22 between the other side of thediaphragm 10 and the base of the wall 17 within the angular wall 18. Theintermediate wall 17 is provided with a nozzle 23 shown integrallyformed therein. Nozzle 23 is generally coaxially located with respect tothe chambers 19 and 22. In the illustrated embodiment of the invention,the nozzle 23 projects downwardly into the chamber 22, terminating inslightly spaced relation to the flat spring 15 with the spring anddiaphragm 10 in the neutral position. The nozzle 23 includes an orifice24 of a preselected diameter.

The opposite side of the intermediate wall 17 is recessed in alignmentwith nozzle 23 to define a second coupling chamber 25, which isconnected to the output ports 4 and 5, in FIGS. 1 4, and having aconcentric, conical portion 26 defining the supply means to the nozzleorifice 24. The chamber is closed by an outer wall, which includes theoutput ports 4 and 5 communicating with the chamber 25. The wall 27further includes a depending nozzle 28 aligned with the nozzle 23 andprojecting downwardly into the conical recess 26. The nozzle 28 extendsthrough wall 27 and includes a lower orifice 29 which is aligned withorifice 24 and having a cross-section somewhat smaller than the orifice24. A top closure wall 30 is secured in overlying relationship to thewall 27 and includes a laterally extending channel 31 interconnected tothe supply port 2 and to the nozzle 28 and establishing a fluid or airstream 32.

In the illustrated embodiment of the invention, the spring 15 includes acentral lid portion 33 connected to an outer ring portion 34 by fouridentical equicircumferentially spaced arms 35. The lid 33 is shown as asquare member. Each of the arms 35 is an L-shaped member, having oneside parallel to and spaced from a corresponding side of the lid 33. Theone end of each arm is connected to the corner of the lid 33 by anintegral extension between the lid and the arm and the opposite end ofthe arm is similarly secured to the ring 34. The second arm portion ofeach arm is spaced outwardly from the first arm portion of an adjacentspring arm. The spring 15 is, thus, a flat disc-like spring with thearms 35 permitting essentially planar inward movement with respect tothe orifice 24 in response to an input pressure signal in the chamber19.

In the operation of the amplifier of FIGS. 1 4, supply to the port 2initially establishes flow through the channel 31, the nozzles 23 and 28to establish a stream 32 into the chamber 22. The vent ports 7 and 8connect to the chamber 22, exhaust the stream pressure and permit thestream flow. The diaphragm 10 is positioned when the forces of the inputpressure signal in chamber 19 and the spring 15 equal the pressure ofthe stream 32 in chamber 22.

With a zero input signal in the input port 11, the spring 15 will assumethe flat, neutral position, with the lid 33 spaced from the collectororifice 24. The supply 3 establishes the stream 32. As previously noted,orifice 29 is somewhat smaller than the orifice 24, and, consequently,the jet stream 32 will flow uniformly through the collector orifice 24.The free flow of the stream 32 will result in aspiration of fluid withinthe output chamber 25, thereby generating a relatively negative orvacuum pressure within the chamber 25. The corresponding pressure is, ofcourse, established and transmitted to the output means 6 through theoutput ports 4 and 5. The output range of the illustrated device istherefore at or below a selected zero reference.

Application of a positive input signal from the control signal source 12through the port 11 creates a corresponding input pressure in thechamber 19. As the input pressure increases, the force of the spring 15and particularly arms 35 is overcome and the diaphragm 10 forces thespring and particularly lid 33 outwardly of the chamber 19. As the lid33 approaches the collector orifice 24, it opposes the free flow of thejet stream 32, thereby effectively reducing the orifice opening anddiverting the flow of the stream 32 into the space between the nozzles28 and 23, resulting in a pressure in the chamber 25 and thus in theoutput ports 4 and 5. The output pressure rises from the negative levelto a positive level and is essentially proportional to the inputpressure until the lid 33 seats against the underside of the orifice 24.The latter condition effectively closes the collector orifice 24 andthereby establishes a maximum output pressure in chamber 25.

The diaphragm amplifier 1 provides a high gain characteristic with thehigh input impedance, as a result of the dead-ending of the input signalinto a closed chamber 19. Further, the dual nozzle construction permitsthe creation of a relatively negative pressure and thereby permitsoperation of the amplifier between a positive and a negative pressureand flow range with a proportional output signal.

Alternatively, the illustrated device is adapted for application to afluid repeater wherein the output pressure is maintained equal to theinput pressure over a selected range, while maintaining the high inputimpedance characteristic. The connection of the apparatus as a fluidrepeater is diagrammatically illustrated in FIG. 6. The structure shownin FIG. 6 has been modified to relocate the ports to clearly illustratethe interconnection of the apparatus in a single view and it will beobvious that the apparatus of the previous embodiment can be similarlyconnectedto function as a repeater.

Referring particularly to FIG. 6, a recessed base 36, with a diaphragm37 and a spring 38 mounted within the recess in the same manner as shownin the previous embodiment, appears therein. An input port 39 issimilarly connected to an input chamber 40 defined by the diaphragm 37.An inverted cup-shaped closure wall 41 is telescoped into the recessedbase 36 and abuts the spring 38 to provide a fluid-tight seal at theperiphery of the diaphragm 37 and spring 38. An intermediate wall 42 issuitably secure in fluid-tight engagement within the cup-shaped wall 41and with the underside of the wall 42 spaced outwardly from the spring38 to define a coupling chamber 43, similar to chamber 22 of theprevious embodiment. The wall 42 includes a connector nozzle 44concentrically located with respect to the diaphragm 37 and spring 38.The backside of the wall 42 is recessed to define a chamber 45 overlyingand extending laterally of the nozzle 44. The closure wall 41 includes anozzle 46 aligned with the nozzle 44 to provide a pair of stacked andspaced nozzles with the space therebetween closed by the chamber 45. Aport 47 is connected to the nozzle 46 and a port 48 is connected to thechamber 45. With the device applied as a repeater the ports 47 and 48are connected to a reference or vent rather than to a pressurized supplyand a main power stream port 49 is connected to the chamber 43. The port49 is connected to a pressured supply 50 through a pressure-dropping orcoupling restrictor 51. In the illustrated embodiment of the invention,an output port 52 is also connected directly to the chamber 43 and to afirst output means 53. A second output means 54 is connected to thedownstream side of restrictor 51. Thus, in the embodiment of FIG. 6, asapplied to the previous embodiment, the two vent ports 7 and 8 (FIGS. 14), respectively, become supply port 49 and an output port 52 and thesupply port 2 and output ports 4 and 5 of such first embodiment (FIGS. 14) are connected to atmosphere or reference.

In the embodiment of FIG. 6, a zero input signal at port 39 places thediaphragm 37 and the spring 38 in the neutral position, allowingrelatively free venting of the chamber 43 to the chamber 45 and thusport 48 and also through nozzle 46 to port 47. The chamber 43 will thusassume the reference pressure and provide a corresponding minimal outputpressure at ports 49 and 52.

As an input signal is applied via the port 39, the pressure in thechamber causes the diaphragm 37 and the spring 38 to deflect outwardlytoward the nozzle 44. This, in turn, will reduce the venting via thenozzle 44 and tend to increase the pressure in chamber 43. The increasein pressure in chamber 43, however, will build-up and tend to oppose theinput pressure in chamber 40. It will reach a balanced position onlywhen the pressure in chamber 43 equals the pressure in chamber 40.Consequently, the pressure in chamber 43 and that appearing in the ports49 and 52 will correspond to the pressure appearing in the input port 39and the output pressure will thus equal the input pressure. Thisbalanced arrangement is maintained for all of the pressures within thecapability of the system. Thus, if the input pressure at port 39 shouldever rise above the maximum available pressure via the restric tor 51,the spring 38 will engage the nozzle 44 and the output pressure willthen be equal to the maximum pressure available. It cannot, of course,increase above such pressure, even should the input pressure signalincrease further.

The output pressure will thus equal the signal input pressure, as longas the input pressure does not rise above the maximum available pressureavailable at the I downstream side of restrictor 51.

The present invention thus provides very simple, reliable diaphragmamplifiers which can be employed in various configurations to provide aproportional high gain amplifier with a high input impedance and alternatively a repeater having a one-to-one gain while maintaining orretaining the high input impedance characteristic.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims, particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

We claim:

1. A fluid diaphragm modulator comprising a chamber means including adiaphragm wall means common to a first coupling chamber and a signalchamber, an input signal means connected to said signal chamber forselectively positioning said diaphragm wall means, a first orifice meansin said coupling chamber in aligned opposed relation to said diaphragmwall means, a second orifice means mounted in spaced aligned relation tosaid first orifice means outwardly of said coupling chamber, said firstorifice means being larger than said second orifice means and beingclosely spaced whereby a stream emitted from said second orifice meansand passing freely through said first orifice means aspirates fluid, asecond coupling chamber means enclosing the space between said first andsecond orifice means, a pressurized fluid supply means connected to saidsecond orifice means and a fluid reference means connected to said firstcoupling chamber whereby a continuous stream is established through saidorifice means with said diaphragm spaced from said first orifice means,and a load means connected to said second cou pling chamber forproviding in response to said input signal an output signal at saidsecond coupling chamber varying from an aspirating condition to saidsupply means pressure in accordance with the position of said diaphragmwall relative to said first orifice means.

2. The fluid diaphragm modulator of claim 1 wherein said orifice meansare essentially coaxial.

3. The fluid diaphragm modulator of claim 1 wherein said diaphragm wallincludes a flat diaphragm secured about the periphery within saidchamber means in opposed relation to said first orifice means, a flatspring means overlying said diaphragm within said chamber and secured atthe periphery, said spring means having a central portion movablelinearly relative to the plane of said diaphragm, and said fluid signalchamber uniformly applying a pressure over the backside of the diaphragmto selectively move the spring means toward the orifice.

4. The fluid diaphragm modulator of claim 3 wherein said flat springincludes an outer ring portion and a central lid portion aligned withsaid first orifice means, and a plurality of equicircumferentiallyspaced arms connected between said ring portion and said lid portion,said arms permitting linear flatwise movement of said lid portion.

5. The fluid diaphragm modulator of claim 1, wherein said chambers areformed in stacked relation with a common wall between said couplingchambers, said first orifice being formed in said common wall, and saidsecond orifice being formed in a wall of said second coupling chamberopposite said common wall.

6. The fluid diaphragm modulator of claim 1, wherein chamber meansincludes a plurality parallel spaced planar walls defining said chamberswith a common wall between said coupling chambers, said first orificemeans being formed by an offset nozzle in said common wall projectinginto said first coupling chamber toward said diaphragm, and said secondorifice means being formed by a similar offset nozzle in the wall ofsaid second coupling chamber opposite said common wall.

7. The fluid diaphragm modulator of claim 6 wherein chambers arecircular and said diaphragm wall means includes a flat disc flexiblediaphragm clamped about the periphery within said chamber means to saidchamber walls, said diaphragm wall means includes a flat spring meansclamped at the periphery in overlying engagement with said diaphragm,said spring means having a central flat lid portion secured to an outerring portion by a plurality of spaced arms, said arms extending radiallyand circumferentially of the lid and permitting linear flatwise movementof said lid portion.

8. The fluid diaphragm modulator of claim 7 wherein said arms includefour circumferentially spaced arms, each of said arms being essentiallyL-shaped with one end secured to the lid portion and the opposite endsecured to the ring portion.

1. A fluid diaphragm modulator comprising a chamber means including adiaphragm wall means common to a first coupling chamber and a signalchamber, an input signal means connected to said signal chamber forselectively positioning said diaphragm wall means, a first orifice meansin said coupling chamber in aligned opposed relation to said diaphragmwall means, a second orifice means mounted in spaced aligned relation tosaid first orifice means outwardly of said coupling chamber, said firstorifice means being larger than said second orifice means and beingclosely spaced whereby a stream emitted from said second orifice meansand passing freely through said first orifice means aspirates fluid, asecond coupling chamber means enclosing the space between said first andsecond orifice means, a pressurized fluid supply means connected to saidsecond orifice means and a fluid reference means connected to said firstcoupling chamber whereby a continuous stream is established through saidorifice means with said diaphragm spaced from said first orifice means,and a load means connected to said second coupling chamber for providingin response to said input signal an output signal at said secondcoupling chamber varying from an aspirating condition to said supplymeans pressure in accordance with the position of said diaphragm wallrelative to said first orifice means.
 2. The fluid diaphragm modulatorof claim 1 wherein said orifice means are essentially coaxial.
 3. Thefluid diaphragm modulator of claim 1 wherein said diaphragm wallincludes a flat diaphragm secured about the periphery within saidchamber means in opposed relation to said first orifice means, a flatspring means overlying said diaphragm within said chamber and secured atthe periphery, said spring means having a central portion movablelinearly relative to the plane of said diaphragm, and said fluid signalchamber uniformly applying a pressure over the backside of the diaphragmto selectively move the spring means toward the orifice.
 4. The fluiddiaphragm modulator of claim 3 wherein said flat spring includes anouter ring portion and a central lid portion aligned with said firstorifice means, and a plurality of equicircumferentially spaced armsconnected between said ring portion and said lid portion, said armspermitting linear flatwise movement of said lid portion.
 5. The fluiddiaphragm modulator of claim 1, wherein said chambers are formed instacked relation with a common wall between said coupling chambers, saidfirst orifice being formed in said common wall, and said second orificebeing formed in a wall of said second coupling chamber opposite saidcommon wall.
 6. The fluid diaphragm modulator of claim 1, whereinchamber means includes a plurality parallel spaced planar walls definingsaid chambers with a common wall between said coupling chambers, saidfirst orifice means being formed by an offset nozzle in said common wallprojecting into said first coupling chamber toward said diaphragm, andsaid second orifice means being formed by a similar offset nozzle in thewall of said second coupling chamber opposite said common wall.
 7. Thefluid diaphragm modulator of claim 6 wherein chambers are circular andsaid diaphragm wall means includes a flat disc flexible diaphragmclamped about the periphery within said chamber means to said chamberwalls, said diaphragm wall means includes a flat spring means clamped atthe periphery in overlying engagement with said diaphragm, said springmeans having a central flat lid portion secured to an outer ring portionby a plurality of spaced arms, said arms extending radially andcircumferentially of the lid and permitting linear flatwise movement ofsaid lid portion.
 8. The fluid diaphragm modulator of claim 7 whereinsaid arms include four circumferentially spaced arms, each of said armsbeing essentially L-shaped with one end secured to the lid portion andthe opposite end secured to the ring portion.